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client-ip=165.204.84.17; helo=satlexmb07.amd.com; pr=C Received: from satlexmb07.amd.com (165.204.84.17) by BN3PEPF00022BC6.mail.protection.outlook.com (10.167.248.219) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.382.8 via Frontend Transport; Thu, 3 Sep 2026 12:01:56 +0000 Received: from sriov-SYS-7048GR-TR.xilinx.com (10.180.168.240) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.46; Thu, 3 Sep 2026 07:01:55 -0500 From: Nikola Prica To: CC: , , , , , , Nikola Prica Subject: [PATCH] PCI: Accept AtomicOps already enabled by the hypervisor Date: Thu, 3 Sep 2026 14:12:18 +0200 Message-ID: <20260903121218.4955-1-nikprica@amd.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: satlexmb07.amd.com (10.181.42.216) To satlexmb07.amd.com (10.181.42.216) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BN3PEPF00022BC6:EE_|DS0PR12MB999104:EE_ X-MS-Office365-Filtering-Correlation-Id: 0ae14a2e-c6f7-4786-4a3f-08df09b326f5 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|82310400026|23010399003|376014|36860700016|18002099003|5023799004|56012099006|10067099003|11063799006; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: w743vpbKjVEAtZLmKkqK3Kj7noYK7bUBT6sfnJoIRZtqcc6Aokx3Zm5Zdu/HpEfuNyK//KeXQz9LIr065n2w5YQ0p32PzpQrlCDDZH1DMXkhhlCgPLhUVO6QXjR6XULv4uV+o6Ar+T0mPnNWvFU3yFZVl/DUcsst7yM8bdF7xXrWgn8HMiFQ3CcfgI0XMJuKrpLb3oCa88IvoK2F6sPsFBFStHP1dZhnmuUn2rNc5uD8p0wLmCx67Q5s0Y+lioqCOyVhqLnVHKgtvz4AgdHva+4jB/v4cRfdzWIK84Jz/ZjGhJBgcvcMCDNU/gq76iD8LC+nGCirF507OHqxY2OpikVGQWikdB43bfCp+oB9En4usljXHSTAanjprvihNYNcsj99cxq8WiFCoBu80nOcrdvBDbAk6Djp7E6AbECp8g/7WW4qzuy4eWzYlxdLJioH X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 03 Sep 2026 12:01:56.6921 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 0ae14a2e-c6f7-4786-4a3f-08df09b326f5 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: BN3PEPF00022BC6.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR12MB999104 From: Nikola Prica pci_enable_atomic_ops_to_root() currently fails when no Root Port is visible. That is common in passthrough guests (ESXi, Hyper-V): the endpoint is assigned to the VM, but the guest topology has no Root Port above it. In those setups the hypervisor may already have enabled AtomicOp Requester Enable on the device. If PCI_EXP_DEVCTL2_ATOMIC_REQ is set, treat AtomicOps as already enabled and return success instead of failing the Root Port walk. Signed-off-by: Nikola Prica --- drivers/pci/pci.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index b2879a6be5f8..7c62c7f31757 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -3768,6 +3768,14 @@ int pci_enable_atomic_ops_to_root(struct pci_dev *dev, u32 cap_mask) return -EINVAL; } + /* + * Some hypervisors already set AtomicOp Requester Enable. If it + * is already set, there is nothing more to do. + */ + pcie_capability_read_dword(dev, PCI_EXP_DEVCTL2, &ctl2); + if (ctl2 & PCI_EXP_DEVCTL2_ATOMIC_REQ) + return 0; + root = pcie_find_root_port(dev); if (!root) return -EINVAL; base-commit: 89a312991dc6e638a36adc43ccb91dbc25504c04 -- 2.34.1